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Merge pull request #2181 from jgouly/madd-opt

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arm64: Combine mul + add into madd
This commit is contained in:
Chris Fallin
2020-09-15 11:52:33 -07:00
committed by GitHub
parent d28abad441 22369cfa0d
commit 1c7fa7f785
1 changed files with 40 additions and 12 deletions
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52
cranelift/codegen/src/isa/aarch64/lower_inst.rs
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@@ -74,23 +74,51 @@ pub(crate) fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
}
Opcode::Iadd => {
let rd = get_output_reg(ctx, outputs[0]);
let rn = put_input_in_reg(ctx, inputs[0], NarrowValueMode::None);
let ty = ty.unwrap();
if !ty.is_vector() {
let (rm, negated) = put_input_in_rse_imm12_maybe_negated(
ctx,
inputs[1],
ty_bits(ty),
NarrowValueMode::None,
);
let alu_op = if !negated {
choose_32_64(ty, ALUOp::Add32, ALUOp::Add64)
let mul_insn =
if let Some(mul_insn) = maybe_input_insn(ctx, inputs[1], Opcode::Imul) {
Some((mul_insn, 0))
} else if let Some(mul_insn) = maybe_input_insn(ctx, inputs[0], Opcode::Imul) {
Some((mul_insn, 1))
} else {
None
};
// If possible combine mul + add into madd.
if let Some((insn, addend_idx)) = mul_insn {
let alu_op = choose_32_64(ty, ALUOp3::MAdd32, ALUOp3::MAdd64);
let rn_input = InsnInput { insn, input: 0 };
let rm_input = InsnInput { insn, input: 1 };
let rn = put_input_in_reg(ctx, rn_input, NarrowValueMode::None);
let rm = put_input_in_reg(ctx, rm_input, NarrowValueMode::None);
let ra = put_input_in_reg(ctx, inputs[addend_idx], NarrowValueMode::None);
ctx.emit(Inst::AluRRRR {
alu_op,
rd,
rn,
rm,
ra,
});
} else {
choose_32_64(ty, ALUOp::Sub32, ALUOp::Sub64)
};
ctx.emit(alu_inst_imm12(alu_op, rd, rn, rm));
let rn = put_input_in_reg(ctx, inputs[0], NarrowValueMode::None);
let (rm, negated) = put_input_in_rse_imm12_maybe_negated(
ctx,
inputs[1],
ty_bits(ty),
NarrowValueMode::None,
);
let alu_op = if !negated {
choose_32_64(ty, ALUOp::Add32, ALUOp::Add64)
} else {
choose_32_64(ty, ALUOp::Sub32, ALUOp::Sub64)
};
ctx.emit(alu_inst_imm12(alu_op, rd, rn, rm));
}
} else {
let rm = put_input_in_reg(ctx, inputs[1], NarrowValueMode::None);
let rn = put_input_in_reg(ctx, inputs[0], NarrowValueMode::None);
ctx.emit(Inst::VecRRR {
rd,
rn,